Study of Heterogeneous Catalysis by Iron-Squarate based 3D Metal Organic Framework for the Transformation of Tetrazines to Oxadiazole derivatives

Goswami, Soumyabrata; Jena, Himanshu Sekhar; Konar, Sanjit

doi:10.1021/ic5003258

Cited by 40 publications

(28 citation statements)

References 31 publications

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“…However, if O11 was changed to nitrogen during the refinement process, the observed thermal ellipsoids no longer gave reasonable parameters, indicating the element is most likely oxygen. The decomposition of the central tetrazine ring of bpztz is likely metal‐assisted, as similar behaviour has been observed in other 1,2,4,5‐tetrazine‐based ligand systems [15–22] . However, to the best of our knowledge, such an asymmetric ring opening not been previously observed in the presence of lanthanides.…”

Section: Resultssupporting

confidence: 83%

“…The initial ligand bpztz has undergone an asymmetric ring opening, with the loss of an N 2 molecule and the gain of one O atom, bonded to C56. Due to the anaerobic conditions used to synthesise 1 , the O11 atom is likely due to the presence of a trace amount of water in the reaction mixture [15, 17, 22] . Along with the loss of the N 2 molecule and the opening of the ring, there is a shift in aromaticity.…”

Section: Resultsmentioning

confidence: 99%

“…However, serendipitous transformation of the ligand might occur upon interaction with the metal centre. This is well highlighted in the family of 1,2,4,5‐tetrazine‐based ligands [15–22] . These molecules are of interest in coordination chemistry due to their facile functionalisation and their redox activity, which can enhance magnetic communication between metal ions [23–26] .…”

Section: Introductionmentioning

confidence: 97%

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Asymmetric Ring Opening in a Tetrazine‐Based Ligand Affords a Tetranuclear Opto‐Magnetic Ytterbium Complex

Richardson

Marin

Zhang

et al. 2020

Chemistry A European J

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We report the formation of a tetranuclear lanthanide cluster, [Yb4(bpzch)2(fod)10] (1), which occurs from a serendipitous ring opening of the functionalised tetrazine bridging ligand, bpztz (3,6‐dipyrazin‐2‐yl‐1,2,4,5‐tetrazine) upon reacting with Yb(fod)3 (fod−=6,6,7,7,8,8,8‐heptafluoro‐2,2‐dimethyl‐3,5‐octandionate). Compound 1 was structurally elucidated via single‐crystal X‐ray crystallography and subsequently magnetically and spectroscopically characterised to analyse its magnetisation dynamics and its luminescence behaviour. Computational studies validate the observed MJ energy levels attained by spectroscopy and provides a clearer picture of the slow relaxation of the magnetisation dynamics and relaxation pathways. These studies demonstrate that 1 acts as a single‐molecule magnet (SMM) under an applied magnetic field in which the relaxation occurs via a combination of Raman, direct, and quantum tunnelling processes, a behaviour further rationalised analysing the luminescent properties. This marks the first lanthanide‐containing molecule that forms by means of an asymmetric tetrazine decomposition.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Asymmetric Ring Opening in a Tetrazine‐Based Ligand Affords a Tetranuclear Opto‐Magnetic Ytterbium Complex

Richardson

Marin

Zhang

et al. 2020

Chemistry A European J

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“…LC-MS analysis of the mixture revealed a major side product with a mass shift of À 22 Da that might correspond to a 5-methyl-1,3,4-oxadiazole derivative (Scheme 2B.3 and Figure S7) formed by hydrazine-catalyzed decomposition, which proceeds similarly to previously described reactions. [50][51] As observed for 4 and 5, purification of HIPS-azide (6) with RP-HPLC led to product decomposition. Interestingly, this was even observed in the absence of TFA and might have been caused due to an increase inherent susceptibility of 6 towards oxidation at the hydrazine moiety.…”

Section: Synthesis Of Hips and Knoevenagel Conjugation Reagentsmentioning

confidence: 71%

Bifunctional Reagents for Formylglycine Conjugation: Pitfalls and Breakthroughs

et al. 2020

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Dedicated to the memory of Thomas Dierks Formylglycine-generating enzymes specifically oxidize cysteine within the consensus sequence CxPxR to C α-formylglycine (FGly). This noncanonical electrophilic amino acid can subsequently be addressed selectively by bioorthogonal hydrazinoiso-Pictet-Spengler (HIPS) or Knoevenagel ligation to attach payloads like fluorophores or drugs to proteins to obtain a defined payload-to-protein ratio. However, the disadvantages of these conjugation techniques include the need for a large excess of conjugation building block, comparably low reaction rates and limited stability of FGly-containing proteins. Therefore, functionalized clickable HIPS and tandem Knoevenagel building blocks were synthesized, conjugated to small proteins (DARPins) and subsequently linked to strained alkyne-containing payloads for protein labeling. This procedure allowed the selective bioconjugation of one or two DBCO-carrying payloads with nearly stoichiometric amounts at low concentrations. Furthermore, an azide-modified tandem Knoevenagel building block enabled the synthesis of branched PEG linkers and the conjugation of two fluorophores, resulting in an improved signal-to-noise ratio in live-cell fluorescence-imaging experiments targeting the EGF receptor.

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“…Studies comprising of Co(II) complexes with 1,3,4-oxadiazole derivatives in which cobalt atom is directly bound to a nitrogen atom of 1,3,4-oxadiazole were focused mainly on biological activities of these compounds, and, sporadically, DC magnetic properties were also reported [20][21][22][23][24][25]. Likewise, a few coordination compounds of Fe(II) with 1,3,4-oxadiazole directly bonded through its nitrogen atom appear in literature, e.g., [Fe(2-bpo) 2 (H 2 O) 2 ](ClO 4 ) 2 (2-bpo = 2,5-bis(2-pyridyl)-1,3,4-oxadiazole) was prepared and found to be in the high spin state in the 2-300 K range [26]. Magnetochemically focused study exploring Light-Induced Excited Spin-State Trapping (LIESST) and SCO in 2,5-bis(2-pyridyl)-1,3,4-chalcadiazoles describes magnetic properties of [Fe(2-bpo) 2 (NCS) 2 ].…”

Section: Introductionmentioning

confidence: 99%

The Structural and Magnetic Properties of FeII and CoII Complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole

et al. 2020

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Two novel coordination compounds containing heterocyclic bidentate N,N-donor ligand 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) were synthesized. A general formula for compounds originating from perchlorates of iron, cobalt, and fpo can be written as: [M(fpo)2(H2O)2](ClO4)2 (M = Fe(II) for (1) Co(II) for (2)). The characterization of compounds was performed by general physico-chemical methods—elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) in case of organics, and single crystal X-ray diffraction (sXRD). Moreover, magneto-chemical properties were studied employing measurements in static field (DC) for 1 and X-band EPR (Electron paramagnetic resonance), direct current (DC), and alternating current (AC) magnetic measurements in case of 2. The analysis of DC magnetic properties revealed a high spin arrangement in 1, significant rhombicity for both complexes, and large magnetic anisotropy in 2 (D = −21.2 cm−1). Moreover, 2 showed field-induced slow relaxation of the magnetization (Ueff = 65.3 K). EPR spectroscopy and ab initio calculations (CASSCF/NEVPT2) confirmed the presence of easy axis anisotropy and the importance of the second coordination sphere.

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Study of Heterogeneous Catalysis by Iron-Squarate based 3D Metal Organic Framework for the Transformation of Tetrazines to Oxadiazole derivatives

Cited by 40 publications

References 31 publications

Asymmetric Ring Opening in a Tetrazine‐Based Ligand Affords a Tetranuclear Opto‐Magnetic Ytterbium Complex

Asymmetric Ring Opening in a Tetrazine‐Based Ligand Affords a Tetranuclear Opto‐Magnetic Ytterbium Complex

Bifunctional Reagents for Formylglycine Conjugation: Pitfalls and Breakthroughs

The Structural and Magnetic Properties of FeII and CoII Complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole

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